M.Covington: New taxa from the Niobrara Formation..., p. 121- 131.

Journal ofNannop1ankton Research, 16, 3, 1994.

NEW TAXA FROM THE NIOBRARA FORMATION(UPPER CRETACEOUS) OF KANSAS, USA
Mitch Covington, Department of Geology, Florida State University, Ta/lahassee, FL 32302 USA
Introduction
Intervals with well preserved nannofossils were studied
from the Upper Turonian - Lower Campanian NiobraraFormation of northwestern Kansas, USA. Extensive scanning electron microscopy of the samples yielded several
new taxa, clusters of monospecific coccoliths which represent collapsed coccospheres, and the first truly cylindrical'coccosphere' published from the fossil record. Covington( 1985) provides discussion on the study area, clusters, andcylindrical forms. The purpose of this paper is to describe
the new species observed in the study. New taxa describedhere include one genus, Watkinsia, and four species,
Watkinsiapedalion,Biscutumdekaenelii,Biscutumzulloi,
and Rotelapil/us applegatei.
All type material is deposited at the Department ofGeology, Florida State University, Tallahassee, Florida,U.S.A.
Acknowledgments
David K. Watkins suggested the study and was helpful inmany other aspects of the ~ !udy. S. W. Wise provided lab
facilities and guidance. Richard Pollastro (USGS, Denver,Co.) provided use of the SEM. Eric de Kaenel was helpful
with taxonomy and review of the manuscript. Jeremy
Young is responsible for resurrecting this portion of athesis project and, with Jackie Burnett, was helpful inreviewing the manuscript. Thanks to these and many
more.
Systematic palaeontology
Biscutum zulloi, new species(Plate I, figures 1-~)
Derivation of name: In honour of the late Dr. Victor
Zullo, University of North Carolina at Wilmington.
Diagnosis: A species of Biscutum distinguished by adouble ro'Yof obliquely oriented overlapping laths bordering the central area margin, and by its long cylindricalcoccosphere.
Description: .The distal rim is of typical Biscutum typewith about 30 petaloid elements. The central area isrelatively wide accounting for approximately 52% of thewidth and 67% of the length.
The outermost cycle of central area elements is adouble row of obliquely oriented overlapping elements
which forms a distinct ridge around the perimeter of thelarge central area. This ''collar'' is distinct in both phase
contrast and cross-polarized light. Inside this collar is anirregular cycle ofblocky elements. The specimens in Plate
1, figures 1 & 3, illustrate wide variation in this cycle ofblocky elements; this variation is probably a function ofpreservation. On well preserved specimens, a small knob
occurs in the centre of the central area.

Biscutum zulloi is the only species ofPalaeopontosphaera or Biscutum observed to form a truly
cylindrical coccosphere (further discussion in Covington,1985). Other non-spherical coccospheres have been ovoid
to subcylindrical in shape (Plate 1, figures 6 & 7).
Remarks: de Kaenel & Bergen (1993) present a revisedclassification of the Jurassic Biscutaceae based on
ultrastructural characteristics, in particular the nature ofcycles around the central area/rim margin. Following
them species with a discrete birefringent inner wall cycle
should be placed in Pa/aeopontosphaera. B. zu/loi falls
within their concept of Palaeopontosphaera, however,
applying their scheme to the Late Cretaceous would
require a wide-ranging revision of the taxonomy of theBiscutaceae, which is beyond the scope of this paper.
Size: The coccoliths of the holotype measure approximately 4.4 by 5.5 11m along the short and long axes
respectively of the distal shield. Including the collar, thecentral area is 2.3 by 3.7 Jlm. Cylindricalcoccospheres thatare known to be complete (closed at the ends) have notbeen observed. The longest specimen found in this study
was approximately 35 J.lm.
Occurrence: Rare to common throughout the Niobrara
Formation (Upper Turonian - Lower Campanian).
Holotype: Plate 1, figures l-3 .
Paratype: Plate l, figures 4-5.
Type locality: Location 18 (Hattin, 1982 ), sample 18/ll827, Smoky Hill Member of the Niobrara Formation,
northwestern Kansas, Western Interior, U.S.A.

Biscutum dekaenelii, new species(Plate 2, figures 5-6)
Genus and species indet., Wise & Wind, 1977; Plate 28, figure 6.

Derivation of name: In honour of Dr. Eric de Kaenel.
Diagnosis: A species of Biscutum with a central areaspanned by a hollow granular cross.
Description: The distal rim of the holotype is composedof 20 petaloid elements. The elements form a steep wallaround the central area, which is bordered by a narrowledge of laths that imbricate clockwise and are roughly
equal in number to the rim elements. The central area
accounts for approximately 50% of the total width of thecoccolith, and 60% of the length. The coarsely granularbars ofthe cross originate from below the ledge oflaths and=========================121==========================

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Journal ofNannoplankton Research, 16,3, 1994.

gradually rise distally, forming a hollow knob. The barsare aligned with the long and short axes of the coccolith.
Remarks: On two occasions. these rare coccoliths were
found in association with clusters of Boletuvelum (Plate 2,figures 1-6), which is also rare. Though further documentation is necessary, this association raises the possibility
that the two coccolith types may have originally belonged
to the same cell. Wise and Wind ( 1977; Plate 28, figure 6)
illustrate a specimen of B. dekaenelii which they list as''Genus and species indet.' ', from a Maastrichtian DSDP
Sample from the Falkland Plateau. On their range chart,
the same sample contained rare specimens of Boletuvelum
candens.
Size: Holotype: Approximately 5 11m long and 3.3 11mwide.

M.Covington: Newtaxafromthe Niobrara Fonnation... , p. 121- 131.

a bedding plane would seemingly rule out overgrowth as
the cause of their basic differences. Other species illustrated show no significant signs of intense overgrowth.
Derivation of name. This subspecies is named in honourof Joseph Applegate, Florida State University Nannofossil
Laboratory, Tallahassee, Florida.
Occurrence. Few to common in a very short intervalwithin the Santonian of the Niobrara Formation of Kansas, Western Interior, North America.
Size. Holotype: Approximately 2. 7 J.lm across the proximal base, and 3 J.lm across the widest, most distal part ofthe rim. Distal ends of stems (rosettes) of two paratypes(Plate 3, figure 7, bottom left) measured 1.6 11m across.
Holotype. Plate 3, figure 7 (middle).

Occurrence: Rare in the upper Coniacian -lower Santonianof the Smoky Hill Member of the Niobrara Formation,Western Interior, North America.
Holotype: Plate 2, figure 5. Same specimen is viewed atlower magnification in Plate 2, figures 3 and 6 in the lower
right of the photograph.
Type locality: Location 12, Marker Unit 5 (Hattin, 1982),
Smoky Hill Member of the Niobrara Formation, northwestern Kansas, Western Interior, U.S.A.

Rotelapillus applegatei new species
Plate 3, figures 2-9
Diagnosis: A species of Rotelapillus distinguished by its
robust radial bars and stem.
Differentiation: The outer rim of R. ellipticum and R.
applegatei are nearly identical, but the radial bars of R.
applegatei fill, or nearly fill, the entire central area to thepoint that the bars are sometimes barely discernible.
Where the stem of R. e/lipticum is fragile to the point that
it is rarely preserved intact, the stem of R. applegatei isvery robust and often 80% as wide as the basket-shaped
rim. The distal end of the stem is terminated by a rosetteof 8 imbricate petals, resembling specimens ofRucinolithus.Because of its robust stem, R. applegatei isusually observed in side view in the light microscope,whereas C. el/ipticum and other members of Rotelapillus
are nearly always seen in proximal or distal view. In sideview, C. applegatei resembles a flat-topped mushroom,and often the distal rosette and the sutures between rim
elements may be distinguished.
Remarks: The specimens are somewhat overgrown and it
is conceivable that the differences between the species may
be an artifact of overgrowth. Plate 3, figure 2, however,illustrates a cluster of C. applegatei with several specimens of C. ellipticum (upper right). The micrograph is ofa fractured surface of chalk broken parallel to bedding,and the coccoliths have presumably experienced the same
diagenetic history. The association of both subspecies onParatypes. Similar specimens in Plate 3, figures 2-8.
Type locality. Location 12, Marker Unit 5 (Hattin, 1982),
Smoky Hill Member of the Niobrara Formation, Northwestern Kansas, Western Interior, North America.

Watkinsia, new genus
Type species: Watkinsia pedalion new species
Derivation of name. In honour of Dr. David K. Watkins,
Department of Geology, University of Nebraska, Lincoln,
Nebraska.
Diagnosis: A large, flat nannofossil that resembles therudder or centreboard ofa sail boat. The assumed proximal
end is thickened in a plane perpenciicular to the flat ''fin''.
In cross-polarized light, the entire specimen goes into
extinction as one unit.
Remarks: This oddly shaped nannofossil has no discernible elements and is somewhat irregular in outline. It
seems highly susceptible to overgrowth and is difficult todistinguish in the light microscope; it appears to be a flat
simple piece of calcite. At present, this is a monospecificgenus. It is possible that these are holococcoliths, withovergrowth having destroyed the original crystallite
ultrastructure.

Watkinsia pedalion new species
Plate 4, figures 1-4
Derivation of name. From 1m&x.A.wv (Greek)- rudder.
Description: In side view, this taxon resembles the centreboard or rudder of a sailboat. In assumed proximal
view, it exhibits an elliptical base. The base has a convex
central area, surrounded by a flat rim, the width of which
is approximately 22% of the total width of the short axisof the base. There are no discernible elements forming the=========================122==========================

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M.Covington: New taxa from the Niobrara Formatioo..., p. 121 - 131 .

Journal ofNannoplanklon Research, 16, 3, 1994.

base. The "rudder" projects perpendicularly from theplane of thebase. It flattens and thins distally and exhibits
an irregular outline when viewed in a plane parallel to thebase.

Type locality: Location 18 (Hattin, 1982), 11 meters
below Bed 27 (Sample 18/11-827), Smoky Hill Memberof the Niobrara Formation, northwestern Kansas, Westem Interior, North America.

Remarks: When observed in side view under the lightmicroscope, the irregular outline and lack ofa distinguishing interference pattern make this species appear as a flatpiece of calcite (Plate 4, figure 4) and hence, difficult toidentify. It goes extinct as a unit in cross-polarized light.

REFERENCES
Covington, J. M., 1985: New morphologic infonnation on
Cretaceous nannofossils from the Niobrara Fonnationof Kansas. Geology, 13, 683-686.
de Kaenel, E., & Bergen, J. A., 1993: New Early and Middle
Jurassic coccolith taxa and biostratigraphy from theeastern proto- Atlantic (Morocco, Portugal, and DSDP
Site 547B). Eclog. Geol. Helv. 8613, 861-907.
Hattin, D. E., 1982: Stratigraphy and depositional environmentof Smoky Hill Chalk Member, Niobrara Chalk (UpperCretaceous) of the type area, western Kansas. Kansas
Geol. Sun•. Bull., 22,108pp.
Wise, S. W., & Wind, F. H., 1977: Mesozoic and Cenozoic
calcareous nrumofossils recovered by DSDP Leg 36
drilling on the Falkland Plateau, southwest Atlantic
sector of the Southern Ocean. IRDSDP, 36, 269-491.

Occurrence: Rare to few in the Santonian of the Niobrara
Formation of northwestern Kansas, Western Interior,U.S.A. .
Size: Holotype: 15 Jlm across the base, 21 Jlm along theaxis perpendicular to the base, and 10 Jlm (mean) acrossthe flat "rudder".
Holotype: Plate 4, figures 1-2.
Paratypes: Plate 4, figure 3.

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Jownal ofNarmoplankton Research, 16, 3, 1994.

M.Covington: New taxa from the Niobnra Fonnation..., p. 121 - 131 .

PLATE 1
Fig. l Scale bar= 10 J.lm; Figs. 2-3, 6-7, Scale bar= 1 J.lm
1-5:

Biscutum zulloi, n. sp.; (1) cylindrical coccosphere; note orderly, spiral arrangement of coccoliths; Sample
18/11-827. (2) same specimen tilted 60°, end view. (3) same specimen, close up. (4) cylindrical coccosphere;
phase contrast; Sample 20/8-Ml5; X2300. (5) same specimen; cross-polarized light.

6-7:

Biscutum constans (G6rka); (6) subcylindrical form; Sample 24/16-859. (7) same specimen tilted 45°; arrows
point to smaller, simpler end-forming coccoliths.

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Journal ofN111110plankton Research, 16,3, 1994.

IM.Covington: New taxa from the Niobrara Formation..., p. 121 - 131.

PLATE2
Fig.1 , Scale bar= 10 J.lm; Figs. 2-6, Scale bar= 1 J.lm
1-4: Bo/etuve/um candens Wind and Wise; ( 1) distal views; Sample 21 fl5- TSH. (2) side view; Sample 21/25-TSH. (3)side view; Sample 12/M5. (4) side view showing interior of the spine and distal view of coccolith (with spinebroken away?).
5-6: Biscutum dekaenelii , n. sp., (5) distal view; Sample 12/M5. (6) same specimen in lower right with additional
specimen in upper left, associated with Bo/etuvelum specimens.

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Journal ofNannoplankton Research, 16, 3, 1994.

M.Covington: New taxa from the Niobrara Formation... , p. 121 - 131.

PLATE3All specimen from Sample l2/M5
Fig. 2, Scale bar= lO 11m; Figs. l, 8-9, Scale bar= l 11m
All light micrographs x 2200
1: Rotelapil/us el/ipticum Bukry, Proximal and distal views.
2-9: Rotelapil/usapplegatei, n. sp., (2)proximal, distal,andsideviews;arrowpointstoR. ellipticum. (3)phasecontrast;side view. (4) same specimen; cross-polarized light. (6) different specimen; cross-polarized light. (7) proximaland distal views; note Rucinolithus-like stem ends (arrows). (8) side views. (9) proximal, distal, and side views.

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IJournal ofNarmoplankton Research, 16, 3, 1994.

M.Covington: New taxa from the Niobrara Fonnation..., p. 121 - 131.

PLATE4All specimens from Sample 18/11-B27
Figs. 1-3, Scale bar= 10 11m

1-4: Watkinsia pedalion, n. gen., ( 1) holotype, proximal(?) view, tilted 60°.; (2) same specimen, side view; (3) Side viewof two paratypes; (4) cross-polarized light.